Hi wonton, If the 'pin' is flush with the outside of the block it is in the factory position to be used with a bypass filter. If it has been driven in it blocks off the main oil galley and you MUST use a full flow filter, utilizing the 1/2 inch tapped holes, or you will toast your bearings. Also, be sure the 'in' side of the oil filter adapter is being fed from the oil pump fitting or the check valve in the filter will block the oil from your engine, and you will toast your bearings. The 'pin' is a drive fit, and once seated was not designed to be removed or repositioned. Just my experience, Tim II#498
